Over the past century, temperature sensitivity of crystal oscillators has been improved by applying temperature compensation algorithms based on the externally sensed ambient temperature. One type of crystal used is the temperature-compensated crystal oscillator (TXCO), a form of crystal oscillator employed where a precision frequency source is required within a small space and at reasonable cost. However, the best performing crystal oscillators rely on ovenization of the resonant device to provide the highest stability, such as the oven-controlled crystal oscillator (OCXO). The evolution of micro electro-mechanical systems (MEMS)-based inertial sensors is likely to follow a similar trajectory due to the similarity of vibrating MEMS devices to quartz oscillators. A typical sensor, resonator and electronics operation temperature range is −40° C. to 80° C., with extended range of −55° C. to 125° C. for industrial and military applications. See U.S. Pat. No. 5,917,272, “Oven-heated crystal resonator and oscillator assembly”; U.S. Pat. 4,985,687, “Low power temperature-controlled frequency-stabilized oscillator”; U.S. Pat. No. 5,530,408, “Method of making an oven controlled crystal oscillator the frequency of which remains ultrastable under temperature variations”; and U.S. Pat. No. 5,659,270, “Apparatus and method for a temperature-controlled frequency source using a programmable IC”. At present, uncompensated MEMS inertial sensors are widely available for commercial applications and digital temperature compensation devices are emerging. Temperature stabilization has been demonstrated to improve long-term stability and reproducibility of MEMS inertial sensors in an academic setting, but has yet to be transitioned into marketable MEMS-based inertial sensors. Similar concepts of operating a resonator or MEMS inertial sensor at a fixed temperature can be applied to any other electronics device or sensor to provide high accuracy, high-stability performance across varying operation environment temperature. In U.S. Pat. No. 8,049,326 (“Environment-resistant module, micropackage and methods of manufacturing same”), K. Najafi et al. proposed an environmental-resistant packaging module to provide a temperature stabilization for inertial sensors on the platform. Dongguk Yang et al. presented a low-power oven control micro platform using glass substrate to achieve 300× improvement of temperature stability of the inertial sensors. See “±2 ppm frequency drift and 300× reduction of bias drift of commercial 6-axis inertial measurement units using a low-power oven-control micro platform”, Proc. 2015 IEEE Sensor Conf., pp. 1-4.
Achieving a high-level of temperature control requires high-precision temperature sensors and electronics. The best commercially available temperature sensor chips provide a few parts per million (ppm) per degree Celsius stability, and thus hundreds of ppm drift over the entire operation temperature range. In addition, the drift of electronic voltage references or current sources required to form the temperature setting of the oven is at best in 2-3 ppm/° C., which will not meet many high stability applications requirements. Therefore, the temperature set point of the oven control platform may drift due to the temperature dependency of the temperature sensors and oven control electronics. For example, in Yang's article, an extra temperature sensor outside the packaged platform was still required to perform a further temperature compensation because the environmental temperature fluctuation may still affect the temperature and stress on the oven control platform.
Therefore, there is a need in the art for a system and method where the set temperature point of the oven control is not affected by the temperature dependency of the temperature sensor and electronics, but determined by the material properties independent of the reference electronic voltage or current. These and other features and advantages of the present invention will be explained and will become obvious to one skilled in the art through review of the present application.